1. Field of the Invention
The present invention relates to fuel injection control systems for internal combustion engines, and more particularly to improvements in fuel injection control systems of the type wherein a plunger cooperates with an adjusting member to determine the beginning and/or termination of fuel admission into the cylinders and thus to control the amounts of injected fuel.
2. Description of the Prior Art
U.S. Pat. No. 3,630,643 to Frang Eheim and assigned to Robert Bosch GmbH discloses a fuel injection pump for internal combustion engines, particularly for diesel engines. The pump comprises an engine-driven distributing member which is installed in the housing and serves to admit metered quantities of fuel to the cylinders of the engine, and a control circuit arranged to produce control signals whose characteristics vary as function of changes in rotational speed of the engine. A transducer means is provided in the housing and responds to the control signals to influence the distribution of fuel by the distributor member, for example by determining the beginning or the termination of fuel injection. The transducer means comprises an electromagnet which is energizable by the control signals and has a rotary armature whose angular position is a function of the characteristics of control signals. The transducer means includes a shaft which is rotatable with the armature, an eccentric mounted on the shaft, a collar surrounding and movable axially of the distributing member to thereby influence the distribution of fuel to the cylinders, and a ball-and-socket connection between the collar and the eccentric.
The pump, however, determines the amounts of fuel injected into the cylinders within a relatively narrow range of rotation angle of the armature by means of the shaft which rotates with the armature. Thus precise control of fuel injection is relatively difficult.
The present invention contemplates more precise control of the fuel amounts injected to the engine cylinders.